A not insignificant fracion of all capital is not in the stock market, but in (generally) far less risky investments like bank accounts, corporate and sovereign bonds, or real estate. As they (usually and in the long run) have a lower return, a higher return on stocks might very well be sustainable even in the long run, as long as economic growth runs at a reasonable clip.

A not insignificant fraction of all capital assets is not in the stock market, but in (generally) far less risky investments like bank accounts, corporate and sovereign bonds, or real estate. As they (usually and in the long run) have a lower return, a higher return on stocks might very well be sustainable even in the long run, as long as economic growth runs at a reasonable clip.

Only assuming that you do not reinject your gains from the stock market into the stock market. If you do, then the stock market's fraction of all assets in the economy will increase.

But why build a factory when you can simply invest in one with less risk and better return? Of course sooner or later you run out of bricks and mortar and are left with paper and electrons, but isn't it loverly while it lasts?